The present invention relates to a rotary device on the head tube for stunt bicycles and the device employs principle of lever to have better force transferring efficiency.
A conventional rotary device 80 for stunt bicycles is shown in FIG. 6 and generally, one of the two brake cables has to be separated into two breads 82 by using a separation device 81 as shown. The two breads 82 of the brake cable are respectively connected to two connection ports 83 on two far ends of a top plate. A lower plate has two connection ports 84 on two far ends thereof and two breads 820 extend from the two connection ports 84 and are connected to a rear brake mechanism. The top plate and the lower plate is connected with each other so that when the breads 82 are pulled, the breads 820 are activated to stop the rear wheel. The other brake cable 820 extends into the steerer tube and the head tube and is connected to a front brake mechanism. The conventional rotary device 80 involves complicated structure and the two breads 82 have to be pulled in balance to properly operate activate the brake system or jam problems could happen. The separation device 81 is an extra part that makes the assembly processes to be complicated.
The present invention intends to provide a rotary device that has simple structure and has a precise force transferring ability which makes the brake actions sharp and precise.
In accordance with one aspect of the present invention, there is provided a rotary device for stunt bicycles. The rotary device comprises a bearing set movably mounted to a steerer tube and has two upright lugs and two downward lugs. A first collar is mounted to the steerer tube and has a first connection portion and a second connection portion respectively radially extending outward therefrom. The two upright lugs are pivotally connected to said first collar. A first lever member has a ring portion is mounted to the steerer tube and has a first connection port and a second connection port respectively radially extending outward therefrom. A first brake cable extends through the first connection port and is connected to the first connection portion of said first collar. The second connection port is pivotally connected to said second connection portion of said first collar. A second collar is mounted to the head tube and has a third connection portion and a fourth connection portion respectively radially extending outward from said second collar. The two downward lugs are pivotally connected to said second collar. A second lever member has a ring portion mounted to the head tube and a third connection port and a fourth connection port respectively radially extend outward from said second lever member. A second brake cable passes through the third connection port and is connected to said third connection portion of said second collar. The fourth connection port is pivotally connected to said fourth connection portion of said second collar.
The primary object of the present invention is to provide a rotary device for stunt bicycles wherein the bearing set is movably mounted to the steerer tube and pivotally connected to the two collars which are respectively connected to two brake cables so that the bearing set play a mediate role to allow the two collars to be pivoted to activate the brake system precisely.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.